2007-02-18 03:09:34 · 7 answers · asked by Anonymous in Science & Mathematics ➔ Earth Sciences & Geology
the earths crust can range from being as deep as 10 km to 40 km. Depending where you are in the world the crust differs in thickness
2007-02-18 03:30:46 · answer #1 · answered by Billy B 2 · 0⤊ 0⤋
The earths crust actually has two different thicknesses. the following is from a web site that is referenced.
Continental Crust
Continental crust is on average older, more silica-rich and thicker than oceanic crust, but is also more variable in each of these respects. The oldest parts of the continental crust, known as 'shields' or 'cratons', include some rocks that are nearly 4 billion years old. Most of the rest of the continental crust consists of the roots of mountain belts, known as 'orogens', formed at different stages in Earth history. Over large areas, however, these orogens are covered by younger sedimentary rocks. New continental crust is still being generated by processes operating at subduction zones. However, sediments eroded from the continental crust and deposited on the ocean floor are also recycled into the mantle at some subduction zones. The average thickness of the continental crust is about 40 km, but beneath parts of the Andes and the Himalaya mountain ranges the crust is more than 70 km thick.
Thickness of the continental crust
Oceanic Crust
Oceanic crust underlies most of the two-thirds of the Earth's surface which is covered by the oceans. It has a remarkably uniform composition (mostly 49% ± 2% SiO2) and thickness (mostly 7 ± 1 km). The ocean floor is the most dynamic part of the Earth's surface. As a result, no part of the oceanic crust existing today is more than 200 million years old, which is less than 5% of the age of the Earth itself. New oceanic crust is constantly being generated by sea-floor spreading at mid-ocean ridges, while other parts of the oceanic crust are being recycled into the mantle at subduction zones. Maps of oceanic crustal ages have been produced as a result of studies of the record of reversals of the Earth's magnetic field which is preserved in the crust as it forms.
2007-02-18 05:00:31 · answer #2 · answered by Anonymous · 1⤊ 0⤋
The Earth's crust varies between about 5 miles under the oceans to about 25 miles under the continents.
2007-02-18 03:22:45 · answer #3 · answered by brainstorm 6 · 0⤊ 0⤋
the outer crust is 2-7 miles deep..
2007-02-18 03:21:07 · answer #4 · answered by m34tba11 5 · 0⤊ 0⤋
7 miles
2007-02-18 03:21:00 · answer #5 · answered by Anonymous · 0⤊ 0⤋
60 km
2007-02-18 03:44:50 · answer #6 · answered by Garette 1 · 0⤊ 0⤋
About as thick as your head.
2007-02-18 03:17:25 · answer #7 · answered by runescape_fan521 1 · 0⤊ 0⤋